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2. Implementation of this Red Data List One aim of this report is to assess the risk of extinction facing bryophytes in Wales so that the current conservation priority list - Section 42 of the Natural Environmental and Rural Communities Act (NERC) 2006, Habitats and species of principal importance in Wales – which was based on 2005 British threat levels (Hodgetts, unpublished, on www.jncc.gov.uk, updating Church et al., 2001), can be modified to take into account species that are threatened in Wales. However, Wales is a political, not biogeographic, area and this list should not be used in isolation without reference to Hodgetts’ revised British Bryophyte Red List (Hodgetts, 2011). Because two threat lists now exist for Welsh bryophytes, some guidance is needed on how these lists should be used, especially given that some taxa have different threat levels in Wales and the whole of Britain. Any taxon that is threatened (Critically Endangered, Endangered, Vulnerable) or Near Threatened in Great Britain (Hodgetts, 2011) should also be regarded as a priority for conservation in Wales, regardless of its threat status in Wales. The bryophytes currently listed under Section 42 are based on the GB Red Data List and this remains legally binding. The categories of threat given by Hodgetts are based on an assessment of national distribution and decline, and apply throughout the current range of each taxon in Great Britain. If a taxon is less threatened in Wales than it is in Great Britain (i.e., it has a lower category of threat than it has in Great Britain as a whole or is even classified as Least Concern in Wales), the Welsh population must still be regarded as a critically important component of the GB population and deserves full protection in Wales with appropriate conservation measures. This is because it represents a part of the whole GB population that has more chance of surviving and recovering than the GB population as a whole. Should the GB population outside Wales continue to decline, the Welsh population will become increasingly important, again regardless of its status within Wales. Should the Welsh population begin to decline, or decline more rapidly than before, the species will be regarded as even more threatened in GB as a whole. Taxa that are more threatened in Wales than they are in Great Britain should naturally be considered as priorities for conservation within Wales. The results of this Red Data List should inform the list of bryophytes that appear on the next revision of Section 42 of the Natural Environmental and Rural Communities Act (NERC) 2006 (Habitats and species of principal importance in Wales). The most pressing issue for bryophyte conservation is that many of the taxa listed here have not been looked for since the 1970s and it is perfectly possible that colonies have been lost without anyone realising. Accurate documentation of the location and size of remaining populations of Wales’ rarest bryophytes is urgently needed. Rhestr Data Coch Bryoffytau ar gyfer Cymru 7
A Bryophyte Red Data List for Wales 8 3. Coverage 3.1 Taxonomic coverage All of the mosses, liverworts and hornworts recorded in Wales have been assessed for this Red Data List. This amounts to 848 taxa according to the latest Census Catalogue (Hill et al., 2008) with two species, Daltonia splachnoides and Schistidium helveticum, added subsequently. These 850 taxa comprise: 587 moss species with 31 additional varieties and 1 additional subspecies; 221 liverwort species with 4 additional varieties and 2 additional subspecies; and 4 hornwort species. A further 22 varieties and one species (Fossombronia husnotii) which were listed in the previous Census Catalogue (Blockeel & Long, 1998) were originally assessed, but many of these have been so poorly recorded in recent decades that it was impossible to determine whether they have declined or merely been ignored recently. Despite this, bryologists tend to take infraspecific taxa very seriously – perhaps more so than vascular plant botanists – and many subspecies and varieties are recorded with as much rigour as species. Some varieties appear to be almost distinctive enough to be species anyway, but are known to intergrade either in Britain or elsewhere in their range. All taxa have therefore been assessed, although some of the less well-known varieties have been placed on the Waiting List or the Data Deficient list. The Schistidium apocarpum aggregate was subdivided by Blom (1996) and is something of a bryological equivalent of the vascular genus Euphrasia (Eyebrights), but thankfully without the hybridisation. Its members have not been evenly recorded in Wales and the status of most remains uncertain. Three that are thought to be particularly uncommon, judging by recent records, are assigned a threat status although S. trichodon was downgraded from Regionally Extinct to Critically Endangered because its apparent loss may not be genuine. Six others are on the Waiting List or Data Deficient list because they are so poorly known. No other bryophyte genus is as taxonomically problematic. Hybrids are much less of an issue in bryophytes than in vascular plants because the hybrid generation is the sporophyte, which is never produced in isolation from the photosynthesising gametophyte generation. The only hybrid sporophytes confirmed from Wales are Weissia brachycarpa x longifolia, although Aphanorhegma patens x Physcomitrium sphaericum has been found just across the border in Cheshire and could occur at the latter’s two Welsh sites. Hybrid sporophytes are not thought to be of conservation concern at present.
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Page 31 and 32: 30 Comments Disjunct from Scotland?

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